1. Field of the Invention
The invention is directed to method and apparatus for depositing a metal layer, more precisely a first contact metal layer, on a contact area of a semiconductor component, preferably of a power semiconductor component, which is arranged in a matrix-like fashion in a wafer assemblage.
2. Description of the Related Art
The prior art, such as disclosed in German Patent Application Ser. No. DE 10 2011 005 743 B3, reveals a method for the electrodeposition of a first contact metal layer on contact areas of a plurality of semiconductor components present in a wafer assemblage and having a pn junction, the p-doped volume region of which adjoins a first surface and the n-doped volume region of which adjoins a second surface and forms second contact areas there. In this case, the second surface of the semiconductor components is enclosed by a contact device in a liquid-tight fashion, wherein the contact device has at least one contact element in electrical contact with second contact areas of the semiconductor components and an external connection element. The semiconductor components with an arranged contact device are introduced into an electroplating bath having at least one electrode and a DC voltage is applied to the electrode and to the connection element of the contact device, as a result of which metal of the electrode deposits at the first contact areas of the semiconductor components. What is problematic, in principle, is that in this case the deposition takes place inhomogeneously, or unevenly, over the wafer assemblage, since it has been found that the deposition takes place to a significantly greater extent at the edge than in the center of a wafer.
There is therefore a need in the art to provide an improved method and apparatus for electrodepositing metal contact areas on (“metallizing”) semiconductor components.